Entities with substantial printing demands often use a production printer such as a continuous-forms printer that prints on a web of print media at high-speed, such as a hundred pages per minute or more. A production printer typically includes a print controller that controls the overall operation of the printing system, and a print engine that physically marks the web. The print engine has one or more printheads each with rows of small nozzles that discharge ink as controlled by the printhead controller. During printing, the printheads and the recording medium move relative to one another as ink is ejected at appropriate times to form a printed image in accordance with image data.
Operators and customers of production printing system may desire an accurate estimation of printing costs prior to printing. Since a production printer may handle a print job having hundreds or even thousands of documents, the amount of ink that is to be used for printing may constitute a large cost component in an estimated price quotation for a customer's print job. Inaccurate ink use estimations may cause a printer to lose highly competitive jobs if ink use estimations are too high or consistently inaccurate.
Some print systems estimate ink usage assuming a constant volume of ink drops ejected from the printhead. However, ink volumes ejected by the printhead tend to vary over time and during the course of printing due to changes in the print environment or conditions of the ink or printhead. Accordingly, ink estimates that assume constant ejection amounts are inaccurate, particularly for large print jobs (e.g., ten thousand feet of printing or more).